Pressure controlling valve system



March 6, 1956 J. w. DICKEY PRESSURE coNTRoLLNG VALVE SYSTEM Filed Oct.30, 1952 5 z3 a a W i 4 M M w w E E @y 7 ai 1M u mv+m 3 n mw 7 E I aEmu.. :rw oo 5 u 6\ /m\ .Ilil Z Mm U 7\l 6 6 w C u@ e 6 y 5 F 1 l 1 1||,r|||||| l 51C BYE United States Patent PRESSURE coNrRoLLING vALvESYSTEM JohnI W. Dickey,.Newlield,.N..Y.assignor to` Bendix AviationCorporation, a-corporation of Delaware Application October 30,. 1952,.Serial No. 317,793 1 Claim.. (c1. 12a-139) The present invention relatesto a pressure controlling valve system for liquid fuelv supplyingdevices and more particularly to an arrangement for limiting thepressure of fuel supplied by a pump to a carburetor or similar fuel"feeding device.

In fuel feeding systems for internal combustion engines in which thefuel' is pumpedvv from a storage tank tothe carburetor, and the level offuel' in the. bowl'. of the carburetor is maintained by a oat-operatedvalve, it is; desirable that the pressure of the fuel at the float valvebe maintained substantially constant irrespective of' the: volume. offuelf admitted by said valve. Otherwise, the fuel level inthe carburetorbowl may vary .with concomitant variations. in the delivery of the fueliets. This requirement necessitates the provision. ofv a pump. systemhaving a much larger capacity than would? be required if considerable.latitude in pressure: betweenA no delivery and fully volume of deliveryycouldy be tolerated. Furthermore, particularlyE whenA constantlyoperating pumpsy of the reciprocating type are employed, there is atendency for fuel' pressures tov buildf up, under conditions. ofinsignificant volume of fuel demand, to. a point where,V liooding, ofthel carburetor may; occur.

Moreovenin fuel feeding `Systems. for' automotive vehicles iny which thefuer feeding; devicev for the internal combustion engine. is suppliedfrom: aremOtelyr located storage tank, it: is desirable that the,y pumpJwhichjtrausfersr the fuel from thev storage taule tothecarburetor belocated: closel to, or actually within, theY tank; in order to avoid theaccumulation of gasified fuel' in the supply conduit;l which condition,popularly' known as; vapor lockp. may render the fuel systemtemporarilyinoperative. However, wherrthe fuel tankl is; locatedf at aconsiderable distance in front' or to,` the rear of the engine as; is;frequentlyV the4 case,y particularly in commercial and milita-ry"vehicles,I the pressure; of; thefuel suppliedv to the carburetor by atan-k mounted pumpf is subject to import-ant variations? due, tothelchanges in the hydrostatic. head between: the ends; of the;v feed lineas; the vehicle ascendsf orj descends: obstructions or decliyities.These variations in pressure-.may affect theflevely of; the fuel in thecarburetor bowl, as controlled by the conventionaltv float"y va1ve,'tosucht an extentv as, to. have a significant effecton. the; fuelymixture. supplied to the engine lt is` an` objectof the presentinvention to provide'k a novel: fuel pressurev controllingvalvesystemfor internal combustion` engines which maintains the, pressureat; thepointjof ldelivery substantial-ly' constant irrespective 'of variationsin theA volume` of fuel'y delivered, and in, the angle of'pitch ofavehicleY on whichgitfmay be mounted. Iti sanother objectto` providesuoli'V a device kwhich is arranged' to# positivelyl prevent pulsationsin pressure of the fuel supplying device from building up pressure atthe point of delivery at times when little or no fuel is being used bythe engine.

It is another object to provide such a device incorporatice ing meansfor automatically increasing the fuel pressure at the carburetor of theengine responsive to opening the throttle. valve in order toI enrich thefuel mixture at times of engine acceleration.

It is another object to provide such a device which is adapted' for useinsealed fuel systems such as those employed on vehicles capable ofoperation while submerged.

Further objects. and advantages will be apparent from the followingdescription taken in connecti n with the accompanying drawing, in which:`f

Fig. l is a semi-diagrammatic illustration1 of a fuel systemincorporating a preferredembodiment of the invention, the pressurelcontrolling valve being shown in longitudinal section;

Fig. 2: is a detail view'of a portion of Fig. v1 showing the structuremodifiedv to. provide for the controlof delivered fuel pressure inaccordance with engine'intake vacuum; and

Fig. 3 is a vertical substantially mid-sectionaly view of anv embodimentof the invention in which the pressurelimiting valve is incorporated asa unit with the' fuel supply pump. A l

In Fig. l of the drawing there is illustrated a fuel supply system foran internal combustion engine comprising a storage tank 1, a fuel pump Zmounted' thereon, a pressure controlling' valve indicated' generally bythe numeral 3y mounted on theV carburetor 4 of the engine, a-nd aconjduitl 5 connecting the fnel pump to the pressurelimiting valve; Itisy to be understood thatthefuel pump maybe of' any suitableconstruction, but it isy preferred toemploy an electromagneticreciprocating type of pump suclr asdisclosedV in thev patent to DickeyVet al., No. 2,472,067 issued .l une17', 1949'.

According-'to the present invention, the pressure-limiting valve 3-comprises a hollow cylindrical body 6 whichis threadedv as showny at 7randl 8 for connection to the conduit 5' and' carburetor 4, respectively,and i's provided withf an internal shoulder 9 against which is locatedan O-ringf, 11 of suitable elastically deformable material such as:rubber or the likev which forms a seat for a conical valve member 112'mounted ona valve stem 13- protruding fromthe valve body 6.

- A dished plate member 14 is rigidly mountedas indicated at 1-5; onthe, end of thevalve body6, and a exible diaphragm 16 is sealed at itsrim to the periphery of the plate memberI 1 4 by' means ofV a cap 17,the rim 18 of which?isgcrirnped'aroundI the peripheries of the diaphragmand plate, preferably with the interposi't'ionA of a suitablesealing-'ring 19'. A clamp nut 21 is threaded? on the protruding endloff the; valve. stem 13 and extends through a central opening in thediaphragm 16". A pressuredis:- tributing disc member 22 is rigidlymounted-on the nut 21 and presses the central portion of the diaphragmi6 against a sealingring 211i.1 which i's backed' by a ange 24 of the.nut,y the di'sc 22 being retained' on the nut'- by suitable. means suchas.` al lip, or flange 25 formedy on the nut.

A spring 26 is mounted on the valvel stem 13', bearing at one end: onanv internal shoulder 2.7 in thev valve body 6and, at its other endpressing againstthe valve member 12 to urge it away from the. valve.seat *1-1' and thereby admit fuel into the chamber28` formed between theplate member 14 and' the. diaphragm 16.

In this, embodiment of the invention, the. capA 17 isy provided withbreather openings 29 which maintain ambient pressure-within the. cap andagainst the outer side of the. pressure-l distributingI plate 22J and'diaphragm 1'6.

In the operation of the device as above described, when the fuel pump 2is in operation, fuel under pressure is supplied to the valve 3, andsince the valve is initially held open by the spring 26, the fuel ilowsinto the chamber 28 and into the bowl of carburetor 4. As soon as thecarburetor bow is filled, its float valve closes in the usual manner.Pressure immediately builds up in the chamber 28 and causes thediaphragm 16 to overcome the pressure of the spring 26 and move thevalve member 12 into engagement with its seat 11. The area of thediaphragm 16 is so related to the strength of the spring 26 that thedesired unit pressure for the carburetor is effective t close the valvemember 12 and prevent further admission of fuel from the feed line,except what is necessary to replace that which is withdrawn from thecarburetor bowl by the operation of the engine.

It is important to note that in this arrangement, the .flow of fuel intothe valve 3 from the conduit S responsive to the action of the pump 2has a tendency to move the valve member 12 toward closed position. Thisinsures that when little or no fuel is being consumed by the engine, thepulsations of pressure from the pump merely tend to press the valvemember 12 more tightly on its seat and thereby prevents the building upof pressure in the chamber 28 beyond the desired normal condition,

In Fig. 2 of the drawing there is illustrated a modification of thevalve structure in which the vents 29 in Vthe cap 17 are eliminated, anda tting 31 is mounted on the cap to receive a conduit 32 which may beconnected either to the air intake to the carburetor or to the intakemanifold of the engine. By this arrangement, the system .becomes sealedfrom the atmosphere whereby the operation is not affected by changes inambient pressure and may be operated normally even though the vehicle ispartially or completely submerged in water. If the connection is made tothe intake manifold, the outer side of the diaphragm 16 is subjected tothe subatmospheric pressure existing in the manifold. Since thisreduction in pressure within the cap 17 assists the fuel pressure in thechamber 28 to hold the valve member 12 against its seat, when a highvacuum exists in the intake manifold, as when the engine is idling, thefuel pressure in the chamber 28 and consequently on the carburetor fioatvalve is reduced. When the throttle is opened to accelerate the engine,however, the concurrent reduction in the intake vacuum is effective tocause a corresponding increase in the fuel pressure in chamber 28 andconsequent enrichment of the fuel mixture supplied to the engine due toraising of the level of the fuel in the carburetor bowl.

In Fig. 3 there is illustrated a form of the invention in which thevpressure-limiting valve structure is incorporated with the fuel supplypump to form a unitary device. The pump illustrated is of the type shownin the patent to Dickey et al., above cited, and comprises a cylindricalcasing 41 which has coaxially mounted therein a cylinder 42 in which ahollow magnetic piston 43 is caused to reciprocate electromagneticallyand thereby pump fuel up .through the piston and a conduit member 44into the outlet chamber 4Q. The conduit has an internal shoulder 45which positions an O-ring 46 of elastically deformable material whichforms the seat for a valve member 47 mounted on a stern 48.

The upper end of the pump casing 41 is ared out to provide a ange 49against which the periphery of a flexible diaphragm 51 is pressed by thecrirnped-over rim 52 of a cap 53 forming the upper end closure of thechamber 40. The center of the diaphragm 51 is fixed to a clamp nut 54screwed on the end of the valve stem 48, by means of a pressureequalizing disc 55 suitably retained on said nut. A nipple 56 is mountedon the cap 53 in alignment wrth the valve stem 48, and loosely surroundsa cylindrlcal extension 57 of the nut 54. The nipple 56 is internallythreaded, and a threaded thimble 58 is adjustably mounted therein andserves as an abutment for one end of a spring 59, the other end of whichpresses against a shoulder 61 on the nut 54, thereby tending to move thevalve member 47 away from its seat 46. The open end of the nipple 56receives a T fitting 62, one socket 63 of which communicates with theintake manifold of the engine by means of a tube 64, while the othersocket 5S admits atmospheric air. Means for modifying the elect ofchanges of intake vacuum on the operation of the pressure-limiting valveis preferably provided in the form of an adjustable throttling valve 66for restricting the passage connecting the pressure chamber 67 above thediaphragm to the intake manifold, and an adjustable bleeder valve 68 forcontrolling the admission of air to said pressure chamber. It will beunderstood that if the system is to be completely sealed for under-wateroperation, the bleeder opening will be connected to the air intake tothe carburetor or to some other convenient source of atmospheric air asby means of a tube 69.

The casing 41 of the pump is provided with a nipple 71 for the receptionof a feed line 72 connecting the pump to the engine carburetor.

In the operation of this embodiment of the invention, reciprocation ofthe plunger 43 forces fuel into the conduit 44, and if the valve 47, 46is open, the fuel is admitted into the chamber 40 in the upper end ofthe pump casing and is conducted from this chamber to the enginecarburetor. When the carburetor bowl is lled, the back pressure in thechamber 40 due to closure of the carburetor float valve operates on thediaphragm 51 t0 draw the valve member 47 against its seat 46 and preventfurther admission of fuel except as it is consumed by the engine. Thepressure in the chamber 40 may be manually adjusted by threading thethimble 58 toward or away from the diaphragm chamber 67, thus placingmore or less pressure of the spring 59 on the equalizing disc 55 anddiaphragm 51. The variation of fuel pressure in the chamber 40responsive to variations in intake vacuum may likewise be controlledmanually by suitable adjustment of the throttling valve 66 and bleedervalve 68.

Although certain structure has been shown and described in detail, itwill be understood that changes may be made in the precise form andarrangement of parts without departing from the spirit of the invention.

In a fuel supply system for internal combustion engines, pressureregulating means including a delivery chamber having an inlet and anoutlet, a valve controlling the inlet comprising a seat facing towardthe inlet and an obturator member movable in the direction of flow toengage the seat and close the inlet, spring means operative to open thevalve, a flexible diaphragm forming a Wall of the chamber opposite theinlet, and means connecting the diaphragm to the obturator operative toovercome the spring means and draw the obturator against its seatresponsive to a predetermined pressure in the delivery chamber;including further a cap member enclosing the iexible diaphragm, andmeans for controlling the pressure in said cap; in which the means forcontrolling the pressure in the cap which encloses the flexiblediaphragm comprises a tubular connection to the intake manifold of `theengine, a tubular connection to the atmosphere, and manually adjustableregulating valves in said connections.

References Cited in the file of this patent UNITED STATES PATENTS2,136,959 Winfield Nov. 15, 1938 2,228,292 Wood Ian. 14, 1941 2,297,129Bohnstedt Sept. 29, 1942 2,315,881 Thomas Apr. 6, 1943 2,341,257 WunschFeb. 8, 1944 2,587,728 Hoskins Mar. 4, 1952 2,611,592 Anderson Sept. 23,1952 2,633,146 Witt Mar. 31, 1953 *we Nu.

